The following
pictures show how it looks like inside a compressor of a refrigerator...

(Note: The cooling system (heat pump) of a refrigerator or an air-conditioner
is a closed gas-system, which becomes inoperative once opened!!! Furthermore,
older systems might contain substances (e.g. CFCs) which can be harmful
to the environment and should be handled according to applicable laws.
Therefore: Do not try to open or manipulate such a system unless you are
authorized and know what you are doing!!!)

The
compressor (still fully functional...)

The
compressor after the (irreversible) removal of the cover:
The cavity contains a motor (in the lower part, also within the
cavity) which is attached to a piston pump (upper part, as seen
in the picture).

...top
view:
The thin copper pipe is the high-pressure outlet, the rest of the
cavity constitutes the low-pressure side (inlet), which is also
partially filled with a special oil (for lubrication and cooling
of the motor plus pump).

The
inner part:
One can clearly see the motor and the piston pump. The whole assemply
was mounted via three springs to avoid vibrations.

The
separated piston pump...
Low-pressure inlet to the left, valve-assembly in the upper part
of the picture, high-pressure outlet to the right.